Chlorinated n-bromoacetamides and process for making them



United States Patent (Mike CHLORINATED N-BRUMOACETAMIDES AND PROCESS FOR MAKING THEM Joseph D. Park and John R. Laeher, Boulder, 0010., and Henry J. Gerjovich, Wilmington, Del., assignors to Arapahoe Chemicals, Inc., Boulder, Cole., a corporation of Colorado No Drawing. Application October 2, 1951, Serial No. 249,388

8 Claims. (Cl. 269-561) This invention relates to novel broininating agents and the process of producing them. More specifically, it relates to the preparation of chlorinated N-bromo-acetamides.

Objects and advantages of the invention forth in part hereinafter and in In general, the invention is directed to the preparation of novel compounds of the formula wherein X is a chlorine atom, Y is a hydrogen atom, m+n is 3, m is from 1 to 3 and n is from to 2. These compounds are prepared by reacting a chlorinated acetamide with bromine and a heavy metal oxide in the presence of a perfluorinated acid solvent. is meant that every hydrogen atom di and trichlorinated N-bromoacetamides EXAMPLE I 0.1 mole of silver oxide in 250 m1. of

clearly, the

To a solution of anhydrous trifiuoroacetic acid, was added 0.2 mole of 2,713,595 Patented July 19, 1955 temperature at 20 three-quarters of the trifluoroacetic acid had been distilled off, a considerable acetamide was obtained. By analysis with potassium iodide and thiosulfate the compound was found to contain 32.98% bromine, While the theoretical amount of bromine indicated by the formula CzHONClsBr is The melting mother liquors. The residue obtained was sublimed at 5 mm. pressure and C. The sublimation residue was dissolved in hot CCL; and cooled. Ten grams of N- bromotrichloroacetamide crystallized as fine plates. A

total conversion of 81% to N-bromotrichloroacetamide was thus obtained.

EXAMPLE II To a solution of 0.1 mole of silver oxide in 250 ml. of anhydrous trifluoroacetic acid, was added 0.2 mole of dichloroacetamide. The reaction mixture was stirred at fluoroacetic acid was removed by distillation at room temperature at 20 mm. pressure. After approximately threequarters of the trifluoroacetic acid had been distilled off, a considerable amount of crystalline material separated EXAMPLE IV To a solution of 0.245 mole of silver oxide and 0.490 mole of trichloroacetamide in 50 ml. of heptailuorobutyric acid was added dropwise with stirring 0.512 mole of bromine. The mixture was stirred for an hour and then the precipitated silver bromide was filtered oil and washed twice with ml. portions of carbon tetrachloride, the washings being retained separately. A quantitative recovery of the theoretical amount of silver bromide was achieved. The heptafiuorobutyric acid was removed from the original filtrate by distillation at 3 mm. pressure. The N-bromotrichloroacetamide which remained was crystallized from the carbon tetrachloride washings referred to above. After purification by sublimation the product melted at 125 C. The conversion of trichloroacetamide to N-bromotrichloroacetamide was 97% of the theoretical value.

These compounds possess unique brominating properties heretofore unknown and unpredictable on the basis of the prior art. These properties will become evident from the studies described below. Thus, a study of the brominating properties of these compounds with cyclohexene demonstrates the enhanced positive character of the bromine atom. In this study it was observed that cyclohexene reacts with N-bromotrichloroacetamide (Equation 1) to yield predominantly N-(Z-bromocyclohexyl)-trichloroacetamide; with N-bromodichloroacetamide (Equation 2) the product is largely 3-bromocyclohexene; with N-bromomonochloroacetamide 3) the product is predominantly 1,2-dibromocyclohexane. In contrast with these results, is the bromination of cyclohexene with N-brornoacetamide (Equation 4), where a 3-bromocyclohexene was obtained.

(Equation H Br 5 C NHCOClz H20 CH 1120 C i 1 +BrNHCOOOh- I l H H2O CH2 2C\ /CH2 H2 H2 2 /C Hie OH l BrNHCOCHCh H2O CH:

H H2O CH /H HzNCOCHClB H2O C C Br H2 3. 1% 5 1 l BrNnooornoi HzC CH2 g H\ /Br Br unidentified products H26 CH2 C Hi C rno on 7 H2O CH 1 B'tNHCOCHa- B1 +HzNCOCH CH 2 mo 0 C H2 H2 It will be noted that the three new compounds give three different products in their reaction with cyclohexene. This result is entirely unexpected in view of the prior art. Even more unexpected is the result that of the three new compounds, it was the dichlorosubstituted acctamide which produced the same product as did the unsubstituted acetamide. One would have predicted that a gradation of properties from unsubstituted N-bromoacetamide to monosubstituted to disubstituted to trisubstituted would be the case rather than the entirely discontinuous variation of properties which was observed.

The reaction of these same new compounds with toluene likewise gives rise to an unusual order of reactivity. It should be emphasized, however, that the order of reactivity is not the same with toluene as was observed with cyclohexene. While all of the compounds react with toluene to produce monobrominated toluencs in yields of 50 to 72%, the constitution of the monobrominated toluencs is very difierent in each case.

o and p isomers it will be seen from the data presented in Table I that unsubstituted N-bromoacetamide produces a monobrominated toluene which is entirely the result of reaction with the side-chain (Equation 5), while the monosubstituted N-brornoacetamide produces almost entirely nuclear substitution (Equation 6). The diand trisubstituted compounds produce both nuclear and side-chain bromination, with the trisubstituted N-brornoacetamide being most like the unsubstituted N-bromoacetamide.

Table I BROMINATION OF TOLUENE AT 103 C.

Percent Type of Substitution Conversion Compound to Monobromotol Percent Percent ucnes Nuclear Side-chain N-bromoacetamide 5O 0 N-bromomonochloroacetamide 7 2 82 18 N-brornodichloroacetamide G4 64 36 N-bromotrichloroacetamidc 58 17 83 From the above studies, it is evident that the chemical behavior of the chlorinated N-bromoactamides could not have been predicted on the basis of classical organic chemistry.

These compounds are useful and new brominating agents and may be utilized in various organic reactions as mild and specific oxidizing agents.

The invention in its broader aspects is not limited to the specific steps and compositions described but departures may be made therefrom within the scope of the accompanying claims without departing from the principles of the invention and without sacrificing its chief advantages.

We claim:

1. A process for producing compounds represented by the formula 75 wherein X is a chlorine atom, Y is a hydrogen atom, the

sum of m+n is 3, m is from 1 to 3 and n is from 0 to 2 in which a chlorinated acetamide of the formula wherein X is a chlorine atom, Y is a hydrogen atom, the

sum of m+n is 3, m is from 1 to 3 and n is from 0 to 2, is reacted with bromine and a heavy metal oxide selected from the group consisting of silver oxide and mercuric oxide in solution in a perfluorinated aliphatic carboxylic acid.

2. A process as defined in claim 1 in which the perfiuorinated acid is trifluoroacetic acid.

3. A process as defined in claim 1 in which the heavy metal oxide is silver oxide.

4. A process as defined in claim 1 in which the heavy metal oxide is silver oxide and the perfluorinated acid is trifluoroacetic acid.

5. A process as defined in claim 4 in which m is 1 and n is 2.

6. A process as defined in claim 4 in which m is 2 and n is l.

7. A process as defined in claim 4 in which m is 3 and n is O.

8. N-bromotrichloroacetamide.

References Cited in the file of this patent Lacher et al., "J. Am. Chem. Soc. vol. 74 (1952) pp. 5578-80. 

1. A PROCESS FOR PRODUCING COMPOUNDS REPRESENTED BY THE FORMULA
 8. N-BROMOTRICHLOROACETAMIDE. 